The present invention relates to a housing-like arrangement for damping the sound produced by a piece of equipment, particularly an internal combustion engine.
More particularly, the present invention relates to a housing arrangement which makes use of the sound-absorbing characteristic of a liquid.
The fact that liquid has a sound-absorbing effect is known, for example, from liquid-cooled internal combustion engines in which water is circulated through a double-walled cylinder housing.
Another known arrangement of this type is the one shown, for example, in German published patent application No. 1,169,205 of Apr. 30th, 1964, which describes a structure where an annular chamber containing liquid is provided for the purpose of cooling and muffling the sound of gaseous streams. One characteristic feature of this arrangement is that the conduits through which the liquid flows are integral parts of the arrangement.
Another known arrangement in which a liquid is held within a sound-damping housing is the one shown in Swiss Pat. No. 224,736 of Dec. 15th, 1942, in which an internal combustion engine is built into a sound-insulating, portable housing having air inlet and outlet channels which are provided with baffles for the purpose of muffling sound. the structure shown in this patent has a double bottom which forms a container for a liquid, but the liquid is not intended to serve as a sound-damping medium, as evidenced by the fact that the liquid is the fuel for the internal combustion engine, so that it is continuously consumed until the spaced is emptied of liquid. In this arrangement, too, the chamber in which the liquid is contained is part of the sound-generating equipment.
Conventional house-like arrangements of the above type have the drawback that due to the fact that they are fashioned as sound-damping structures, they are heavy and are therefore difficult to transport. This is particularly so in the case of the structure shown in the mentioned Swiss patent because the internal combustion itself is built into the housing-like sound-damping arrangement.
It is, therefore, the primary object of the present invention to provide a housing-like sound-damping arrangement which is readily transportable and which can be used for sound-damping purpose in conjunction with various pieces of sound-generating equipment.